Batteries produced by a manufacturing company have had a life expectancy of 135 hours. Because of...

Batteries produced by a manufacturing company have had a life expectancy of 135 hours. Because of an improved production process, the company believes that there has been anincreasein the life expectancy of its batteries. A sample of 42 batteries showed an average life of 140 hours. From past information, the standard deviation of the population is known to be 24 hours.

a.Start by writing down the null and alternative hypotheses.

b.Next, calculatethe relevant test statistic.

c.What conclusion can be made at the .10 level of significance? Make sure to interpret in words.

Solutions

Expert Solution

orchestra answered 1 year ago

Next > < Previous

Related Solutions

Question 10 "D" size batteries produced by MNM Corporation have had a life expectancy of 87...

Question 10 "D" size batteries produced by MNM Corporation have had a life expectancy of 87 hours. Because of an improved production process, the company believes that there has been an increase in the life expectancy of its "D" size batteries. A sample of 36 batteries showed an average life of 88.5 hours. Assume from past information that it is known that the standard deviation of the population is 9 hours. Using a 0.01 level of significance, the observed value...

A company manufacturing batteries says that its batteries will last 1400 hours. Suppose that the life...

A company manufacturing batteries says that its batteries will last 1400 hours. Suppose that the life times of the batteries are approximately normally distributed, with a mean of 1450 hours and a standard deviation of 60 hours. a) What proportion of the batteries will last less than 1400 hours? b) What is the probability that a randomly selected batteries will last at least 1550 hours? c) How many hours would represent the cutoff for the top 10% of all batteries?...

A manufacturer of AAA batteries wants to estimate the mean life expectancy of the batteries. A...

A manufacturer of AAA batteries wants to estimate the mean life expectancy of the batteries. A sample of 25 such batteries shows that the distribution of life expectancies is roughly normal with a mean of 44.25 hours and a standard deviation of 2.25 hours. Construct a 98% confidence interval for the mean life expectancy of all the AAA batteries made by this manufacturer

A company makes batteries that have life spans with a mean of 3000 hours and standard...

A company makes batteries that have life spans with a mean of 3000 hours and standard deviation of 70 hours. Find the probability that the mean life span of a random sample of 85 batteries will be over 3020 hours.

A company produces refrigerator motors. These engines have a life expectancy of 19.4 years with a...

A company produces refrigerator motors. These engines have a life expectancy of 19.4 years with a standard deviation of 4.8 years. Assume that the service life of the motors is normally distributed. a) Calculate the probability of an engine operating for less than 12 years. Calculate the probability of an engine operating for more than 25 years. Calculate the probability that the life of an engine is between 10 and 20 years. In order to promote the sale of their...

A company has discovered that a recent batch of batteries had manufacturing flaws, and has issued...

A company has discovered that a recent batch of batteries had manufacturing flaws, and has issued a recall. In a group of 15 batteries covered by the recall, 3 are dead. Two batteries at random are chosen from the package of 15 b) Create a probability model for the number of good batteries chosen. c) What's the expected number of good batteries? d) What's the standard deviation?

Presently, the mean life expectancy ofa rare strain of bacteria is l2 hours A scientist claims...

Presently, the mean life expectancy ofa rare strain of bacteria is l2 hours A scientist claims that she has developed a medium and therefore disagrees with this hy pothesis that it is not 12 hours. The scientist tests 25 cultures and finds that they have a mean life of 15.25 hours with s 2 hour. Do these results show that the medium is effective in increasing the bacteria's life expectancy? (Use a-1%) a. State the null and alternative hypothesis b....

Independent random samples from four different brands of recently produced batteries were placed on a life...

Independent random samples from four different brands of recently produced batteries were placed on a life test. The following lifetimes (in minutes) were recorded. Brand A Brand B Brand C Brand D 110 118 108 117 113 116 107 112 108 112 112 115 115 117 108 119 112 119 109 118 a) Provide an outline for the design of this experiment. b) Identify the response variable. c) Create a graph for this data. Can you see a difference in...

A battery company claims that their batteries last on average 60 hours. The standard deviation of...

A battery company claims that their batteries last on average 60 hours. The standard deviation of the battery life is 4 hours. Assuming that their claim is true, what would be the lowest 5% of values we would get if we were to sample 100 batteries and find their mean life length? Please show me how to do it, thank you!

A battery company claims that their batteries last on average 60 hours. The standard deviation of...

Subjects